Aminoplast resins are thermosetting resins made by the reaction of an aminoplast resin precursor (e.g., an amine such as melamine, urea, or an amide) with an aldehyde (e.g., formaldehyde). The resins can be used in a variety of applications, including molding, protective coatings, ion-exchange resins, and adhesives, to name but a few. Common thermosetting aminoplast resins are trimethylol melamine, methylol urea, dimethylol urea, ethylene diamine, benzoguanamine, fully alkylated melamine, and partially alkylated melamine. Aminoplast resins are also highly useful as cross-linking agents for other polymers, such as acrylic polymers (e.g., amino- or hydroxyl-functional: acrylic polymers, polyesters, epoxides, phenolics, and urethanes). Alkylated aminoplast resins (e.g., butylated trimethylol melamine) are useful as cross-linking agents.
One problem with aminoplast resins is related to the aldehyde used in the formation of the resin. The aldehyde is usually not fully consumed during the reaction with the aminoplast resin precursor, so some residual aldehyde is present in the uncured resin. Also, when the resin is cured, relatively large quantities of aldehyde are released as a result of the curing stage. Many aldehydes, such as formaldehyde, exhibit undesirable toxic and carcinogenic properties. It would thus be desirable if reductions could be achieved in the level of aldehyde present in uncured aminoplast resins and/or the amount of aldehyde released during the cure of aminoplast resins. It is toward this goal that the present invention is directed.